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MINI 02 - Immunotherapy (ID 92)
- Event: WCLC 2015
- Type: Mini Oral
- Track: Biology, Pathology, and Molecular Testing
- Presentations: 1
- Moderators:P. Forde, S.J. Antonia
- Coordinates: 9/07/2015, 10:45 - 12:15, Four Seasons Ballroom F3+F4
MINI02.08 - Bidirectional Cross-Talk between CD14+ Monocytes and Human Lung Cancer Cell Lines Results in Different Phenotypic and Functional Outcomes (ID 2497)
10:45 - 12:15 | Author(s): A. Dietz
Myeloid cell infiltration of the tumor microenvironment is associated with decreased overall survival in multiple tumor types, including lung cancer. This myeloid cell infiltration represents a tissue component of the heterogeneous group of cells termed myeloid derived suppressor cells (MDSC), which can inhibit the endogenous anti-tumor response, direct angiogenesis, and promote tumor progression. In several studies of patients with non-small cell lung cancer (NSCLC), there is wide variation in the presence of myeloid cells in the tumor with increasing levels peripheral blood MDSC associated with poor survival. We have previously shown that CD14+ monocytes can be converted by the tumor microenvironment to an immune suppressive phenotype in non-Hodgkin lymphoma and glioblastoma. In this work, we expand on our earlier observations to include recruitment of CD14+ cells by lung cancer cell lines and their conversion to an immune suppressive phenotype. While most models of myeloid cells in the microenvironment describe the effects of these cells on non-malignant systems, we show that myeloid cells may have profound direct effects on the tumor.
Human lung cancer cell lines were cultured and supernatants collected for ELISA. CD14+ cells were isolated from the peripheral blood of healthy volunteers using anti-CD14 immunomagnetic beads. Lung cancer cell lines and CD14+ cells were cocultured under a variety of low serum conditions with or without cisplatin. Changes in CD14+ cell HLA-DR expression and tumor cell survival were measured by flow cytometry. CD14+ cell migration through a permeable transwell membrane was measured in real time with live cell imaging.
Under normal culture conditions, 7 of 8 human lung cancer cell lines secreted detectable levels of CCL2, a major chemoattractant for monocytes, ranging from 30 to 10,000 pg/ml of CCL2 found in culture supernatants. CD14+ cells more robustly migrated towards cell lines with higher production of CCL2. The coculture system showed a differential impact on monocytes by the tested lung cancer cell lines which either reliably upregulated or downregulated CD14+ cell expression of HLA-DR. In 3 of 8 lung cancer cell lines, CD14+ cell HLA-DR was downregulated in a manner expected to promote local immune suppression. Under serum starvation conditions, one lung cancer cell line showed improved survival when cocultured with CD14+ cells. Similarly, coculture with CD14+ cells enhanced tumor survival of two cell lines after exposure to cisplatin.
The studied lung cancer cell lines differ in the degree of CD14+ cell recruitment, CD14+ cell HLA-DR expression after coculture, and level of conferred survival benefit under stressful conditions. Taken together these results suggest that the variable myeloid involvement in lung cancer patients can be modeled using lung cancer lines. In addition, we have identified that for some tumors, monocytes confer a significant survival advantage that is not associated with immune or angiogenic responses. Future work is needed to explore the impact of CD14+ cells on lung tumor invasiveness, angiogenesis, and the mechanisms underlying these pro-tumor effects.
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